What causes small thick bumps on the scalp?

Updated April 17, 2017

Small, thick bumps can form on the scalp for a number of reasons but usually are due to a skin condition. The bumps, usually off-white in colour, can reach the size of a dime and can be removed by scratching them off with your fingers. See a dermatologist to determine the exact cause of your bumps and get advice on how to treat them.

Seborrheic Dermatitis

This type of dermatitis causes the overproduction of oil on the scalp and irritates the scalp with the malessizia yeast fungus. The excess oil and the dandruff from the skin irritation clump together to form hard bumps on the scalp. This condition affects up to 5 per cent of the population, mostly men, and usually comes to a peak in infancy or middle age.

Dry or Oily Scalp

A dry or oily scalp, especially paired with infrequent shampooing, can lead to bumps forming on the scalp. With a dry scalp, the dry, dead skin cells form together on the scalp and around the hairs. On an oily scalp, the oil traps dirt and dead skin and hardens to form a bump. Shampooing irregularly does not allow you to clean these impurities off your scalp on a regular basis, giving you even larger bumps and possibly leading to acne.


Folliculitis happens when your hair follicles become infected with the Staphylococcus aureus or Pseudomonas aeruginosa bacteria. Like other bacteria, these two thrive in damp environments and can even be transmitted in hot tubs. The bacteria agitate your skin and inflame the follicles into red bumps that fill with puss and harden to create white bumps on your scalp.

The puss-filled lesions can occur anywhere on the body but are commonly found on the scalp because they are more likely to happen in hairy, sweaty areas such as your scalp, legs and upper thighs.

Scalp Psoriasis

Psoriasis is an autoimmune disorder, meaning your immune system mistakes healthy body tissues as an illness and attacks them. Psoriasis and inverse psoriasis affect different areas of skin on the body, including the scalp. If you have psoriasis on your scalp, you'll notice elevated red bumps covered in scales of greyish-white skin cells. Psoriasis is a hereditary condition that affects about 2 per cent of the population, and the risk of developing it increases if you are a regular smoker.

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About the Author

Chelsea Baldwin began writing professionally for local newspapers in 2008. She has published articles in “High Country Press” and “Kernersville News.” She also produced newsletters for a local chapter of AIESEC, a global nonprofit organization. She earned a Bachelor of Science degree in journalism from Appalachian State University.